Image editing

I searched "Rainbow Bridge cats" on Google Images recently. One of my favorite is the Stairway to Heaven drawing, which has been edited and modified many times. Here are the versions that have cats:

The picture on the right is correct; someone reversed it and and changed the colors while creating the other image. Does anyone know if there is a way to merge them to have both the cats on the stairway and in the sky (assuming I can flip the image on the left) without making it look goofy? I am Photoshop illiterate.